The aim of this study was to establish the clinical features of extraintestinal infections caused by Hafnia alvei. Over a 5-year period (1994-1998), data were collected regarding inpatients (n = 8) with nosocomial (n = 5) or community-acquired (n = 3) infections caused by Hafnia alvei. The mean age of the patients was 47 +/- 21 years. Three patients had hospital-acquired urinary tract infections. Hafnia alvei also caused community-acquired cholangitis, cholecystitis, appendicitis, psoas abscess and prosthetic endocarditis. Hafnia alvei was susceptible to amoxicillin/clavulanic acid and to first-generation cephalosporins in two cases. Susceptibility to aminoglycosides, imipenem, cotrimoxazole, ciprofloxacin, piperacillin and cefotaxime was very good (8/8). Four patients required invasive treatment.